1. Technical Field
The present invention relates to a measurement system of communication device for carrying out various kinds of measurements relating to communication devices.
2. Background Art
In radio broadcasting, the signal into which a sound signal is modulated by using modulation methods such as AM modulation and FM modulation is sent from a broadcasting station. Hence, a radio receiver outputs an original sound signal by demodulating the signal that it has received in accordance with the modulation method. However, since elements such as transistors and inductors configuring a tuner in the radio receiver varies in characteristics even though they have same element constants, using same elements to configure the tuner does not necessarily result in unified characteristics of tuners as a whole. Hence, there has been a case that a sound signal after being demodulated is deformed, and that output level thereof decreases.
Then, in the production process of radio receiver sin general, deformation and output level of the sound signal demodulated by the radio receiver are measured, and the element constant is adjusted based on the result of measurement.
FIG. 7 is a diagram of a conventional measuring system that measures characteristics of a radio receiver A measuring system 500 shown in this figure measures deformation and output level of a signal demodulated by a radio receiver 502, and is configured by including a signal generator 504, a low frequency analyzer 506, a personal computer 508 and a display unit 510.
In the case where deformation and output level of the signal demodulated by the radio receiver 502 are measured by using the measuring system 500, measurement condition data such as carrier wave frequency and modulation methods are transmitted from the personal computer 508 to the radio receiver 502 and the signal generator 504. The signal generator 504 outputs the signal for measurement into which a predetermined audio signal is modulated, in accordance with measurement condition data outputted from the personal computer 508. The radio receiver 502, on the other hand, demodulates the signal for measurement outputted from the signal generator 504 in accordance with the measurement condition data outputted from the personal computer 508, and outputs the signal obtained by the demodulation to the low frequency analyzer 506. The low frequency analyzer 506 measures deformation and output level of this demodulated signal, and then outputs the result of measurement to the personal computer 508. The personal computer 508 displays the result of measurement outputted from the low frequency analyzer 506 on the display unit 510 to notify the measurement operator thereof.
However, the above described conventional measuring system 500 must comprise the personal computer 508 and the display unit 510, thus making the configuration thereof more complicated, increasing costs and making it necessary to secure an installation space. Furthermore, the personal computer 508 must be connected to each radio receiver 502, causing work-hours in the production process including adjustment and inspection to be increased.
Also, in a mobile telecommunication device such as cellular phone, whether demodulation processing and modulation processing are properly done is measured, and various kinds of adjustments are performed based on the result of measurement. FIG. 8 is a diagram of a conventional measuring system that measures the characteristics of a mobile telephone. As shown in this figure, a measuring system 550 measures deformation and output level of the signal demodulated or modulated by a mobile telephone 552, and is configured to include a signal generator 554, a low frequency analyzer 556, an audio frequency signal generator (AF generator) 558, a transmission analyzer 560, a personal computer 562 and a display unit 564.
In the case where deformation and output level of the signal demodulated by the mobile telephone 552 are measured by using this measuring system 550, operation is performed as in the case with the measuring system 500 shown in FIG. 7.
Furthermore, in the case where deformation and output level of the signal modulated by the mobile telephone 552 are measured by using this measuring system 550, the personal computer 562 gives an instruction to output an audio signal for measurement towards the AF generator 558, and measurement condition data such as carrier wave frequency and modulation methods are transmitted towards the mobile telephone 552. The mobile telephone 552 modulates the audio signal for measurement outputted from the AF generator 558, and then outputs the modulated signal to the transmission analyzer 560. The transmission analyzer 560 measures deformation and output level of this modulated signal, and outputs the result of measurement to the personal computer 562. The personal computer 562 displays the result of measurement outputted from the transmission analyzer 560 on the display unit 564 to notify the measurement operator thereof.
However, similarly as the case with the measuring system 500 shown in FIG. 7, since it is necessary to provide the personal computer 562 and the display unit 564, there rises the disadvantage of a higher cost and a difficulty in securing an installation space, and causes labor in the production process to be increased.